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| United States Patent |
5,151,235
|
|
Reed
|
September 29, 1992
|
Process of making phenylene sulfide/biphenylene sulfide copolymer pipe
Abstract
An improved pipe is produced from phenylene sulfide/biphenylene sulfide
copolymers. The improved pipe has greater flexibility and ductility than
pipe produced from normal PPS resin. Such pipe is produced by preparing a
phenylene sulfide/biphenylene sulfide copolymer and forming the copolymer
into essentially amorphous pipe by extrusion followed by rapid and uniform
quench to avoid pipe crystallization. Such amorphous pipe also can be
oriented by subsequent die extrusion.
| Inventors:
|
Reed; Jerry O. (Bartlesville, OK)
|
| Assignee:
|
Phillips Petroleum Company (Bartlesville, OK)
|
| Appl. No.:
|
556685 |
| Filed:
|
July 23, 1990 |
| Current U.S. Class: |
264/209.5; 264/209.7; 264/211.12; 264/290.2; 264/331.11; 525/535; 525/537 |
| Intern'l Class: |
B29C 055/22; B29C 055/26; 331.11; 331.12 |
| Field of Search: |
264/141,209.1,209.3,209.4,209.5,209.7,210.1,210.7,211.12,211.13,288.4,290.2
428/36.9,419,910
525/535,537
528/388
|
References Cited
U.S. Patent Documents
| 3354129 | Nov., 1967 | Edmonds, Jr. et al. | 528/388.
|
| 3966688 | Jun., 1976 | Campbell | 525/537.
|
| 4274993 | Jun., 1981 | Narisawa et al. | 525/537.
|
| 4775571 | Oct., 1988 | Mizuno et al. | 428/419.
|
| Foreign Patent Documents |
| 222199 | May., 1987 | EP | 264/209.
|
Primary Examiner: Tentoni; Leo B.
Attorney, Agent or Firm: Kinsinger; David L.
Claims
That which is claimed is:
1. A method of producing pipe which comprises:
(a) preparing a copolymer of phenylene sulfide and biphenylene sulfide;
(b) forming said copolymer into essentially amorphous pipe by extrusion
followed by rapid and uniform quench to avoid pipe crystallization; and
(c) drawing said essentially amorphous pipe uniaxially by subsequent die
extrusion.
2. A method in accordance with claim 1, wherein said subsequent extrusion
is performed by extrusion means capable of drawing said amorphous pipe
longitudinally at a longitudinal draw ratio and expanding said amorphous
pipe transversely at a transverse draw ratio at elevated temperatures to
give biaxial orientation.
3. A method in accordance with claim 2, wherein extrusion means is operated
at temperatures in the range of from about 80.degree. C. to about
115.degree. C.
4. A method in accordance with claim 2, wherein extrusion means is operated
at temperatures in the range of from about 85.degree. C. to about
110.degree. C.
5. A method in accordance with claim 2, wherein said subsequent die
extrusion is performed with a pipe pulloff rate in the range of from about
0.1 cm/minute to about 100 cm/minute.
6. A method in accordance with claim 2, wherein said subsequent die
extrusion is performed with a pipe pulloff rate in the range of from about
0.5 cm/minute to about 50 cm/minute.
7. A method in accordance with claim 2, wherein the axial draw ratio of
said subsequent die extrusion is in the range of from about 1.5.times. to
about 8.times..
8. A method in accordance with claim 2, wherein the longitudinal draw ratio
of said subsequent die extrusion is in the range of from about 2.times. to
about 7.times..
9. A method in accordance with claim 2, wherein the transverse draw ratio
of said subsequent die extrusion is in the range of from about 1.5.times.
to about 4.times..
10. A method in accordance with claim 2, wherein the transverse draw ratio
of said subsequent die extrusion is in the range of from about 2.times. to
about 3.times..
11. A method of producing pipe which comprises:
a) pelletizing a phenylene sulfide/biphenylene sulfide copolymer by first
extrusion means operated at temperatures in the range of from about
300.degree. C. to about 320.degree. C.;
b) drying the thus pelletized copolymer;
c) forming the thus dried, pelletized copolymer into essentially amorphous
pipe by second extrusion means operated at temperatures in the range of
from about 300.degree. C. to about 310.degree. C. followed by rapid and
uniform quench to avoid pipe crystallization; and
d) orienting the thus formed essentially amorphous pipe by subsequent die
extrusion by third extrusion means operated at temperatures in the range
of from about 85.degree. C. to about 110.degree. C., wherein the
subsequent extrusion is performed with a pipe pulloff rate in the range of
from about 0.5 cm/minute to about 50 cm/minute with a longitudinal draw
ratio in the range of about 2.times. to about 7.times. and a transverse
draw ratio in the range of about 2.times. to about 3.times..
12. A method comprising melt extruding a phenylene sulfide/biphenylene
sulfide copolymer to form a pipe and cooling the thus-extruded pipe at a
rate sufficient to quench said copolymer forming said pipe to provide an
essentially amorphous pipe and heating said pipe to a temperature of about
the glass transition temperature or above the glass transition temperature
of said copolymer and mechanically stretching said pipe.
13. A method in accordance with claim 12, wherein said pipe is stretched
longitudinally.
14. A method in accordance with claim 12, wherein said pipe is stretched
transversely.
15. A method in accordance with claim 12, wherein said pipe is stretched
longitudinally and transversely to give biaxial molecular orientation.
16. A method in accordance with claim 12, wherein said melt extruding is
performed at temperatures in the range of from about 300.degree. C. to
about 310.degree. C.
17. A method in accordance with claim 12, wherein said thermally
mechanically stretching of said pipe is performed at temperatures in the
range of from about 85.degree. C. to about 110.degree. C.
18. A method in accordance with claim 15, wherein said pipe is stretched
longitudinally with a longitudinal draw ratio in the range of from about
2.times. to about 7.times..
19. A method in accordance with claim 15, wherein said pipe is stretched
transversely with a transverse draw ratio in the range of from about
2.times. to about 3.times..
Description
BACKGROUND OF THE INVENTION
This invention relates to a phenylene sulfide (PS)/biphenylene sulfide
(BPS) copolymer and the production thereof. In another aspect, it relates
to an amorphous pipe.
The use of poly(phenylene sulfide) resins, hereinafter sometimes referred
to as PPS resin, to produce pipe is known; however, normal PPS resin
yields pipe that is crystalline and brittle. For commercial use, a
non-brittle pipe that is more flexible and ductile is needed.
SUMMARY OF THE INVENTION
It is the object of this invention to produce a pipe from PPS resin that is
non-brittle and is more flexible and ductile than pipe produced from
normal PPS resin.
It is a further object of this invention to produce an amorphous PPS pipe.
A further object is to produce a pipe which is flexible after orienting.
In accordance with this invention there is provided a pipe comprised of
phenylene sulfide/biphenylene sulfide copolymer. In accordance with
another aspect of this invention, an amorphous pipe comprised of PS/BPS
copolymer is oriented by die extrusion to produce a an oriented pipe that
is flexible.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram showing a preferred process for the
production of pipe using a PS/BPS copolymer.
FIG. 2 is a longitudinal cross sectional view of a die extrusion apparatus
that can be used to uniaxially orient pipe.
FIG. 3 is a longitudinal cross sectional view of a die extrusion apparatus
that can be used to biaxially orient pipe.
DETAILED DESCRIPTION OF THE INVENTION
The PS/BPS copolymer may be produced by the conventional methods. The
copolymerization can be carried out as broadly disclosed in Campbell, U.S.
Pat. No. 3,919,177 and Edmonds and Scoggins, U.S. Pat. No. 4,116,947, the
disclosures of which are hereby incorporated of reference.
For example, a phenylene sulfide/biphenylene sulfide copolymer is prepared
by, first, mixing at least one suitable source of sulfur with at least one
alkali metal carboxylate and at least one organic amide. With suitable
sulfur sources other than alkali metal sulfides and alkali metal
bisulfides, at least one base is also required. Also, it is preferable to
use a base when the alkali metal bisulfides are employed as sulfur
sources. Next, the mixture is heated, dehydrated, and then combined with
two or more halogenated aromatics for the polymerization.
In accordance with a highly preferred method of making the phenylene
sulfide/biphenylene sulfide copolymers, an aqueous sodium hydroxide
solution is first mixed with an aqueous sodium bisulfide (NaSH) solution,
sodium acetate, and N-methyl-2-pyrrolidone (NMP). Next, the mixture is
heated, dehydrated, and then combined with para-dichlorobenzene (p-DCB),
1,2,4-trichlorobenzene (TCB), and 4,4'-dibromobiphenyl.
Generally, the amount of 4,4'-dibromobiphenyl used in the polymerization is
in the range of 1 to 15 mole percent (based on the p-DCB and
4,4'-dibromobiphenyl charge). Preferably, this amount is in the range of 3
to 10 mole percent, and more preferably, this amount is about 4 to 8 mole
percent.
Generally, the amount of 1,2,4-trichlorobenzene used in the polymerization
is in the range of 0.05-0.8 mole percent (based on the p-DCB and
4,4'-dibromobiphenyl charge). Preferably, this amount is in the range of
0.1-0.6 mole percent, and more preferably, this amount is in the range of
0.2 to 0.4 mole percent.
The temperature at which the polymerization can be conducted can vary over
a wide range and will generally be within the range of from about
230.degree. C. to about 450.degree. C. The reaction time will be within
the range of from about 10 minutes to about 3 days and preferably about 1
hour to about 8 hours. The pressure need be only sufficient to maintain
the halogenated aromatics and the organic amide substantially in the
liquid phase, and to retain the sulfur source therein. Preferably, the
polymerization mixture is heated to about 230.degree. C. and held for
about 2 hours and then heated to about 265.degree. C. and held for about 3
hours.
The phenylene sulfide/biphenylene sulfide copolymer produced for use in
this invention can be separated from the reaction mixture by conventional
procedures, for example, by filtration of the polymer followed by washing
with water, or by dilution of the reaction mixture with water, followed by
filtration and water washing of the polymer. Preferably, deionized water
is added to the reactor at the end of the polymerization time and the
contents are cooled to about 100.degree. C. and filtered. The polymers are
then slurried with ambient deionized water, filtered, slurried twice with
hot (175.degree. C.) deionized water and dried.
The copolymers produced for use in this invention will have melt
viscosities, as measured as melt flows according to ASTM D-1238 at
316.degree. C. with a 5 kg weight, suitable for extruding amorphous pipe.
In general, suitable melt flows will be between about 10 and about 100
g/10 min., preferably between 30 and 70 g/10 min.
The resulting polymers are then prepared to be extruded into pipe.
Preferably, the resulting polymers are pelletized using any extrusion
equipment capable of reaching extrusion temperatures, then dried before
being extruded into pipe. Generally, the pelletization is performed using
extrusion equipment with a die temperature in the range of from about
280.degree. C. to about 340.degree. C. Preferably, the die temperature is
in the range of from about 300.degree. C. to about 320.degree. C.
Generally, the pellets are dried at about 150.degree. C. for about 2 hours
before being extruded into pipe.
In accordance with this invention, the PS/BPS copolymer is extruded into
pipe. It is essential that the profile being formed be nearly cylindrical
and preferably essentially cylindrical.
Generally, the PS/BPS copolymers are extruded into pipe using any
extruders, dies, quenching equipment, and takeoffs suitable for producing
the amorphous pipe product of this invention. This equipment should be
capable of reaching extrusion temperatures in the range of from about
280.degree. C. to about 340.degree. C. and capable of rapid and uniform
quench of the extruded pipe to avoid polymer crystallization. Preferably,
the equipment is capable of reaching extrusion temperatures in the range
of from about 300.degree. C. to about 310.degree. C. Generally, the pipe
is quenched by either water spray from around the die opening or by means
of a water bath. Preferably, quenching is done by extruding hot pipe
directly from the pipe die into a water bath containing cool water. The
pulloff rate speed will vary widely depending on the equipment used, pipe
diameter, and wall thickness desired. This rate can be between 25 cm/min
to 100 cm/min or higher. The pipe wall thickness can vary depending on
ability of the quench system to cool the pipe to prevent crystallization
and on the desired final oriented pipe wall thickness. In general, the
amorphous pipe wall thickness will be about 2 mm to about 6 mm. A pipe
outside diameter will be selected based on available pipe die sizes, die
extrusion sizes, and the requirements for the oriented pipe.
After extrusion, the pipe of the present invention is essentially
amorphous. The density of the pipe is preferably in the range of from
about 1.30 g/cc to about 1.32 g/cc. More preferably, the density is about
1.31-1.32 g/cc. For many utilities, additives such as carbon black,
antioxidants, u.v. stabilizers or pigments may be present at levels which
may effect the density of the pipe while not deletariously affecting pipe
formation or orientation.
In one embodiment of the invention, the amorphous pipe is then molecularly
oriented. By "molecular orientation" is meant a preferred arrangement of
certain axis or planes of molecules with respect to a given axis or plane.
This molecular orientation can result in vastly altered strength,
elongation, modulus, impact, and other values.
In one embodiment of the invention, the amorphous pipe is oriented by
subsequent die extrusion. This subsequent die extrusion is performed by
any die extrusion equipment capable of drawing or stretching the polymer
uniaxially or biaxially at elevated temperatures.
Of course, all extrusion broadly involves a die, including the formation of
the pipe precursor for the oriented PS/BPS copolymer pipe of this
invention. By "die extrusion" is meant a subsequent die shaping in which
the copolymer pipe at orientation temperature is stretched radially and/or
longitudinally and is distinguished from the general term "extrusion".
Preferably, it is simultaneously stretched both radially and
longitudinally to give biaxial orientation.
By "orientation temperature" is meant that temperature, on reheating, at
which the amorphous pipe will orient. Generally, this temperature is
around or above the glass transition temperature (Tg).
Preferably, the die extrusion equipment is operated at temperatures in the
range of from about 80.degree. C. to about 115.degree. C. More preferably,
the die extrusion temperature is in the range of from about 85.degree. C.
to about 110.degree. C.
Generally, the takeoff rate for the die extrusion equipment is in the range
of from about 0.1 cm/minute to about 100 cm/minute. Preferably, the
takeoff rate is in the range of from about 0.5 cm/minute to about 50
cm/minute. Generally, the draw ratios in the longitudinal or machine
direction are in the range of from about 1.5.times. to about 8.times..
Preferably, they are in the range of from about 2.times. to about
7.times.. Generally, the draw ratios in the hoop or transverse directions
are in the range of from about 1.5.times. to about 4.times.. Preferably,
they are in the range of from about 2.times. to about 3.times..
Preferably, no significant amount of crystallization occurs during this
die extrusion process.
Although the wall thickness of the oriented copolymer pipe of this
invention will vary widely depending on the wall thickness of the starting
amorphous pipe and on the draw ratios chosen for the orientation, they
will generally be from about 0.1 to about 3 mm, preferably 0.2 to 2 mm.
FIG. 1 is a schematic diagram of a preferred process for the production of
PS/BPS copolymer pipe. First, PS/BPS copolymers are produced by any
conventional method. Second, the resulting copolymers are pelletized using
any extrusion equipment capable of reaching extrusion temperatures, then
dried. Third, the copolymer pellets are extruded into pipe using any
extrusion equipment capable of reaching extrusion temperatures. Fourth,
the pipe is quenched by any method capable of rapid and uniform quench to
avoid pipe crystallization. Finally, the resulting amorphous pipe is
oriented by subsequent die extrusion.
FIG. 2 is cross-sectional drawing of a die extrusion apparatus capable of
drawing or stretching a polymer uniaxially at elevated temperatures. In a
preferred embodiment of this invention, an essentially amorphous pipe
comprising PS/BPS copolymer 10 is passed between a heated die 12 and a
mandrel 14 to produce a die drawn (oriented) pipe 16. The resulting die
drawn pipe 16 is stretched and thus molecularly oriented in the
longitudinal or machine direction.
FIG. 3 is a sectional drawing of a die extrusion apparatus capable of
drawing or stretching a polymer biaxially at elevated temperatures to give
a molecularly biaxially oriented pipe. In a preferred embodiment of this
invention, an essentially amorphous pipe comprising PS/BPS copolymer 10A
is passed between a heated die 12A and a mandrel 14A to produce a die
drawn (oriented) pipe 16A. The resulting die drawn pipe 16A is stretched
in the longitudinal or machine direction and also in the hoop or
transverse direction.
The amorphous copolymer pipe of this invention is translucent and
non-brittle. It can be used for transporting chemicals and slurries at
moderate temperatures (below the crystallization temperatures) where good
chemical resistance is needed and where it is useful to be able to observe
the flow of materials to locate flow problems or plugs. The oriented pipe
is flexible and can be used as a non-flammable, insulating wrapper or
support for electrical wiring. It can be slit after orientation and opened
to form an oriented film for use in electrical and electronic
applications.
The following examples are provided to further illustrate the invention and
are not to be considered as unduly limiting the scope of this invention.
EXAMPLES
In the following examples, melt flow (MF) values were determined by the
method of ASTM D-1238, condition 316.degree. C./5 kg modified to use a 5
minute preheat, the value of the polymer melt flow being expressed as g/10
min. Density values were determined with a gradient density column and are
expressed as g/cc. Annealed samples for density determination were
prepared by breaking a small piece of the pipe (including the entire
cross-section) and annealing it in a forced air oven at 200.degree. C. for
15 minutes. Differential scanning calorimetry (DSC) values of glass
transition temperature (Tg) and crystalline melting point (Tm) peak were
determined from premelted and quenched samples on a Perkin-Elmer DSC-2C
differential scanning calorimeter equipped with a data station.
Pipe samples were cut to the desired length and tested as prepared or
annealed at 200.degree. C. for 30 minutes in a forced air oven. Quick
burst pressure values in psig were determined on 48 cm long pipe samples
plugged at both ends by increasing the internal pipe pressure until pipe
failure occurred or until the maximum pressure (about 1500 psi) of the
testing unit was reached.
Physical properties of die extruded pipes were determined by cutting
dogbone shaped specimens in both the longitudinal and transverse
directions and testing them on an Instron Tensile Tester.
4,4'-Dibromobiphenyl monomer, purchased from American Hoechst Corp., was
98.5% pure and the remainder of the monomer was monobromobiphenyl.
Meta-dichlorobenzene (meta-DCB) was purchased from Standard Chlorine
Chemical Co., Inc. and contained 42.8 wt. % meta-DCB, 47.2 wt. % para-DCB,
and 7.7 wt. % ortho-DCB.
Die extrusions of the pipe samples were carried out on a presently
preferred embodiment of die extrusion apparatus as shown in FIG. 3. The
die extrusion apparatus comprised an electrically heated die 12A with the
same die diameter as the pipe 10A. A mandrel 14A was supported inside the
pipe 10A and increased in diameter downstream of and immediately after the
die diameter. The longitudinal (machine) draw was controlled by the speed
at which the oriented pipe 16A was pulled from the die 12A. The transverse
(hoop) draw was controlled by the diameter of the mandrel 14A after the
die 12A. A heated chamber surrounded the die extrusion apparatus. Pipe die
extrusion was started by shaping the pipe end to the mandrel size in a
heated oil bath. The pipe was pulled at slow speed through the die until
some orientation had occurred and then the speed was increased to the
desired speed.
POLYMERIZATIONS
Polymers used in the following examples were polymerized as described here.
An aqueous sodium hydroxide solution was mixed with an aqueous sodium
bisulfide (NaSH) solution, sodium acetate, and NMP. This mixture was
heated, dehydrated, and then combined with two or more halogenated
aromatics for the polymerization. All polymers were prepared with
para-dichlorobenzene (p-DCB) and 1,2,4-trichlorobenzene (TCB). In some
runs, part of the P-DCB was replaced with other monomers to study the
effect of various comonomers. Polymers 5, 6, and 7 were prepared with
4,4'-dibromobiphenyl (6 mole percent of the total p-DCB and
4,4'-dibromobiphenyl charge). Polymers 8, 9, and 10 were prepared with
meta-dichlorobenzene (m-DCB) (8 mole percent of the m-DCB and p-DCB
charge). A sufficient amount of the m-DCB/P-DCB monomer mixture was used
to give the indicated m-DCB monomer content. Each polymerization mixture
was heated to about 230.degree. C. and held for about two hours and then
heated to about 265.degree. C. and held for about three hours.
At the end of the polymerization time for polymer 1, the polymerization
mixture was concentrated by partial solvent flashing at about 265.degree.
C. The concentrated PPS slurry was further flashed at about 240.degree.
C., washed with ambient temperature water, and filtered. After the polymer
had been slurried with hot (190.degree. C.) water and filtered, it was
dried to yield polymer 1.
At the end of the polymerization time for the other polymers 2-10,
deionized water was added to the reactor and the contents were cooled to
about 100.degree. C. and filtered. Polymers 2-10 were slurried with
ambient deionized water, filtered, slurried twice with hot (175.degree.
C.) deionized water, and dried.
EXAMPLE I
This example illustrates the difficulties in producing die extruded PPS
pipe using polymers outside the scope of the present invention. Four PPS
samples were prepared using only p-DCB and TCB as halogenated aromatics.
The TCB levels, expressed as a mole percent of the p-DCB, are shown in
Table 1 with the polymer melt flow (MF) values.
TABLE 1
______________________________________
PPS POLYMERS
TCB, MF,
Polymer mole % g/10 min
______________________________________
1 0.22 50
2 0.275 21
3 0.275 28
4 0.20 44
______________________________________
The four polymers were pelletized using melt temperatures of about
300.degree.-330.degree. C. and 325 mesh screens for Polymers 1 and 4, a
200 mesh screen for Polymer 3, and no screens for Polymer 2. The pellets
were dried at 125.degree.-150.degree. C. for several hours and extruded
into pipe using a 38 mm diameter Davis-Standard extruder equipped with a
pipe die. The 33 mm outside diameter pipe was extruded using internal air
pressure (14-22 psig) and a plug in the pipe open end. A water spray from
around the die opening was used for cooling pipe from Polymers 1 and 2. A
water bath was added for pipe from polymers 3 and 4 to improve pipe
cooling. The pipe samples are described in Table 2.
Polymer 1 was extruded at a die temperature of about 305.degree. C. and a
takeoff rate of about 580 mm/min to produce pipe with a wall thickness of
about 3 mm. A similar pipe produced later under similar conditions had a
density of 1.360 g/cc and a density of 1.366 g/cc after annealing at
200.degree. C. for 15 minutes. The relatively small change in density on
annealing and the original opaque pipe appearance indicate that the
extruded pipe was already largely crystalline. The pipe burst strength was
high. Attempts to orient the pipe from Polymer 1 by subsequent die
extrusion were unsuccessful.
TABLE 2
______________________________________
PPS Pipe
Pipe
Pellet Wall
MF, Thickness, Density,
Burst,
Polymer g/10 min mm g/cc psig
______________________________________
1 50 3 1.360.sup.a)
1700.sup.a)
2 ND.sup.b) 1 1.327 ND.sup.b)
3 28 3.9 1.346 >1500.sup.c)
4 ND.sup.b) 3 1.336 >1500.sup.c)
______________________________________
.sup.a) Determined on similar pipe samples made at a later time.
.sup.b) Not Determined.
.sup.c) Sample did not break at the indicated pressure.
Polymer 2 was extruded into pipe with a takeoff speed of about 152 cm/min
to produce pipe with a wall thickness of about 1 mm and a density of 1.327
g/cc. The density, transparency, and flexibility of the pipe indicate an
essentially amorphous pipe. This pipe could be easily die extruded at
temperatures of about 86.degree.-90.degree. C. and rates up to about 40
cm/min. However, the die extruded pipe wall thickness was only about
0.2-0.4 mm at longitudinal draw ratios of up to about 1.8.times. and
transverse draw ratios of up to about 2.1.times..
Pipe extrusions from Polymers 3 and 4 were carried out using a water bath
about 152 cm long containing cool (about 24.degree. C.) water. The hot
pipe was extruded directly from the pipe die into the water bath. Pipe
from Polymer 3 was extruded using a takeoff speed of 47 cm/minute and had
a density of 1.346 g/cc (Table 2) and wall thickness of 3.9 mm. Polymer 4
was extruded with a takeoff speed of 58 cm/min into pipe with a wall
thickness of 3 mm and a density of 1.336 g/cc. From their densities and
opaque appearances, these pipe samples were appreciably crystalline and
would not be suitable for die extrusion.
The results in this example show that pipe extruded from normal PPS
crystallizes rapidly when the pipe wall thickness is relatively thick
(about 3-4 mm thick). Thin-walled pipe (about 1 mm thick) can be quenched
to the essentially amorphous state and then die extruded. However, the
thin, starting wall thickness limits the thickness of the die extruded
product. In addition, orientation from the rapid takeoff during pipe
extrusion limits the amount of draw possible during die extrusion.
EXAMPLE II
This example demonstrates the preparation in accordance with the invention
of die extruded pipe from copolymers designated as Polymers 5, 6, and 7.
Polymers 5, 6, and 7 were polymerized as described above using 6 mole
percent 4,4'-dibromobiphenyl (based on the p-DCB and 4,4'-dibromobiphenyl
charge) and the amount of 1,2,4-trichlorobenzene shown in Table 3. The
polymer melt flows ranged from 3 to 71 g/10 minutes. Compared with DSC
values for a PPS similar to Polymer 1 of 94.degree. C. for the Tg and
273.degree. C. for the Tm, the DSC results shown in Table 3 for Polymers
5, 6, and 7 indicate higher Tg values and lower Tm values for these
copolymers.
TABLE 3
______________________________________
Phenylene Sulfide/Biphenylene Sulfide Copolymers
TCB,.sup.a)
MF, Tg, Tm,
Polymer mole % g/10 min .degree.C.
.degree.C.
______________________________________
5 0.4 3 101 251
6 0.4 28 97 261
7 0.2 71 97 255
______________________________________
.sup.a) Mole % of the pDCB and 4,4dibromobiphenyl charge.
Polymers 6 and 7 were pelletized on a 38 mm diameter single screw extruder
using a 200 mesh screen in the breaker plate and a die temperature of
316.degree. C. Pellets from Polymers 6 and 7 were dried at 150.degree. C.
for two hours and extruded into pipe using the extruder and pipe die
described in Example I along with the pipe quench bath. Polymer 6 was
extruded into pipe with a die temperature of 313.degree. C. and 13 psig
internal air pressure. Polymer 7 was extruded into pipe with a die
temperature of 293.degree. C. and 16 psig internal air pressure. In both
extrusions a pipe pulloff rate of 58 cm/min. was used and a pipe wall
thickness of about 3 mm was obtained.
The pipe products from Polymers 6 and 7 are described in Table IV. Pipe
from Polymer 7, based on the low density and clear cross-section, was
essentially amorphous. Pipe from Polymer 6 had a slightly higher density
than pipe from Polymer 7 and had indications of a crystalline region in
the center of the pipe cross-section. Apparently, during the extrusion of
the pipe from Polymer 6, the bath temperature increased to allow traces of
crystallization to occur in the center of the pipe wall from slower
cooling. Annealed pipe from Polymer 7 had a slightly decreased burst
strength compared with the as-extruded pipe.
TABLE 4
______________________________________
Phenylene Sulfide/Biphenylene Sulfide Copolymer Pipe
Pellet Pipe
MF, Density, Burst,
Polymer g/10 min Annealed g/cc psig
______________________________________
6 27 no 1.328 >1400.sup.a)
yes 1.350 >1200.sup.a)
7 53 no 1.314 >1400.sup.a)
yes 1.348 .sup. 1075
______________________________________
.sup.a) Samples did not break at the indicated pressure.
Polymer 7 pipe was die extruded using the extruder and pipe die described
in Example I at die temperatures of 86.degree.-110.degree. C. and takeoff
rates between 0.5 and 42 cm/min. Longitudinal or machine direction draw
ratios as high as 6.3.times. and hoop or transverse draw ratio up to about
2.4.times. were obtained. Test results on several of the die extruded pipe
samples of Polymer 7 are shown in Table 5. A variety of physical
properties were obtained depending on the drawing conditions. The die
extruded samples had densities of 1.316-1.317 g/cc, indicating that no
significant amount of crystallization occurred during the die extrusion
process.
TABLE 5
__________________________________________________________________________
Pipe Die Extrusion for Polymer 7
Tensile
Strength
Draw Draw Ratio
Wall Thickness, mm
MPa
Die Speed,
Hoop
Longit.
Hoop Longit.
Hoop
Longit.
Temp., .degree.C.
mm/min
Dir.
Dir.
Dir. Dir. Dir.
Dir.
__________________________________________________________________________
105 5 2.41
2.04
0.7-0.8
0.9-1.0
81 71
103 5 2.40
2.86
0.6-0.7
0.65-0.7
60 68
110 18 2.39
6.30
0.3-0.3
0.3-0.5
48 103
__________________________________________________________________________
The results in this example show that pipe extruded from PS/BPS copolymers
can be quenched to an essentially amorphous state, even when the pipe wall
thickness is relatively thick (about 3-4 mm thick). These resulting
essentially amorphous pipes can then be drawn to give tough biaxially
drawn pipe with reasonably balanced properties in the machine and hoop
directions.
EXAMPLE III
This example illustrates another copolymer made with meta-dichlorobenzene
(meta-DCB) and para-dichlorobenzene (para-DCB). These copolymers are
outside the scope of the present invention and are not suitable for
extrusion into relatively thick, amorphous pipe that can be die extruded.
Three copolymers, Polymers 8, 9 and 10, were prepared using 8 mole percent
meta-DCB, based on the total m-DCB plus p-DCB charge, and the level of
1,2,4-trichlorobenzene shown in Table 6. The melt flow values for Polymers
8, 9, and 10 ranged from 17 to 84 g/10 min. The DSC Tg and Tm values
(Table 6) for polymers 8, 9, and 10 are lower than for a PPS similar to
Polymer 1 (94.degree. C. for Tg and 273.degree. C. for Tm).
TABLE 6
______________________________________
Meta-DCB/Para-DCB Copolymers
TCB,.sup.a)
MF, Tg, Tm,
Polymer mole % g/10 min .degree.C.
.degree.C.
______________________________________
8 0.5 17 82 232
9 0.4 34 84 231
10 0.4 84 81 234
______________________________________
.sup.a) Mole % of mDCB and pDCB charge.
Polymers 8, 9, and 10 were pelletized on a 38 mm diameter single screw
extruder using a 200 mesh screen in the breaker plate and die temperatures
of 320.degree., 316.degree., and 304.degree. C., respectively. Pellets
from Polymers 8, 9, and 10 were dried at 150.degree. C. for two hours and
extruded into pipe using the extruder and pipe die described in Example I
along with the pipe water bath. Pipe was extruded from Polymers 8, 9, and
10 using 16 psig internal air pressure and die temperatures of
310.degree., 299.degree., and 304.degree. C., respectively. In all
extrusions, a takeoff rate of 58 cm/min. was used and a pipe wall
thickness of about 3 mm was obtained.
The pipe products from Polymers 8, 9, and 10 are described in Table 7.
Although the pipe samples as extruded have nearly the same density
(1.329-1.331 g/cc), pipe from Polymer 8 had indications of crystallinity
in the center of the pipe wall, whereas the other two pipe samples from
Polymers 9 and 10 had clear cross-sections. Annealed samples of the pipe
from Polymers 8, 9 and 10 had about the same density (1.361-1.362 g/cc)
and exhibited lower burst strengths than the original pipe samples from
Polymers 8, 9 and 10.
TABLE 7
______________________________________
Meta-DCB/Para-DCB Copolymer Pipe
Pellet Pipe
MF, Density, Burst,
Polymer g/10 min Annealed.sup.a)
g/cc psig
______________________________________
8 12.5 no 1.331 >1400.sup.b)
yes 1.361 .sup. 880
9 28 no 1.329 >1400.sup.b)
yes 1.361 .sup. 920
10 56 no 1.329 >1400.sup.b)
yes 1.362 --
______________________________________
.sup.a) Annealed at 200.degree. C. for 15 minutes for density and 30
minutes for the burst test.
.sup.b) Samples did not break at the indicated pressure.
Attempts to die extrude the pipe products of this example were unsuccessful
due to pipe splitting in the machine direction.
The results in this example show that copolymers made with meta-DCB and
para-DCB can be die extruded to form pipe with clear cross-sections. This
resulting pipe, however, cannot be oriented by subsequent die extrusion
without longitudinal splitting of the pipe.
The results in the foregoing examples show that pipe extruded from PS/BPS
copolymers can be quenched to an essentially amorphous state then oriented
by subsequent die extrusion, even when the pipe wall thickness is
relatively thick (about 3-4 mm thick). Pipe extruded from other PS
polymers and copolymers cannot be oriented by subsequent die extrusion
unless the wall thickness of the pipe is relatively thin (about 1 mm
thick).
From the foregoing examples and data it will be seen that phenylene
sulfide/biphenylene sulfide copolymers are suitable for the production of
extruded pipe which is non-brittle and is more flexible and ductile than
pipe extruded from other arylene sulfide homopolymers and copolymers.
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